1. Field of the Invention
The present invention relates to a wireless terminal, a wireless controller, a core-network device, and a wireless base station, which are specifically used for wireless communication through a femtocell.
2. Description of the Related Art
Currently, femtocells are beginning to be used in the field of wireless communication. Each femtocell covers a small area (cell), so that the dead zone of the electromagnetic wave in a house or an office can be eliminated, and exclusive use of one or more wireless resources is allowed. Therefore, wireless communication using femtocells enable more stable securement of high-speed communication than the conventional wireless communication.
When a user starts femtocell-based communication, for example, the user presses down a call button on a wireless terminal such as a mobile phone. The wireless terminal starts processing for call connection when the call button is pressed down.
The processing for call connection is constituted by wireless-link connection between the wireless terminal and a RAN (radio access network) and wireless-access-line connection between the wireless terminal and a CN (core network). Specifically, when the wireless terminal receives from the user a request to start a communication (communication-start request), the wireless terminal establishes a wireless link with the RAN through a wireless base station (Node B) arranged for femtocell-based communication. Then, the wireless terminal and the CN perform processing for authentication and concealed communication through the Node B and an RNC (radio network controller), and establishes a wireless access line between the wireless terminal and the CN. Thus, the wireless terminal can perform communication with an opposite party.
In a previously proposed network service system, an area to which a mobile body is to move is predicted, and communication resources are allocated in advance, as disclosed, for example, in Japanese Unexamined Patent Publication No. 2000-502521. In addition, in a previously proposed channel reservation system, when the reception level, at a wireless terminal, of a signal from a base station in a first area adjacent to a second area in which the mobile terminal currently exists exceeds a predetermined level, a reservation for the mobile terminal is made so that the traffic from or to the mobile terminal is not interrupted by movement of the mobile terminal from the second area to the first area, as disclosed, for example, in Japanese Unexamined Patent Publication No. 6-121373.
However, in the systems in which a wireless link and a wireless access line are established after reception of a communication-start request from a user, it takes much time until the communication is started.